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Gunma University, 1-5-1 Tenjin-cho, Kiryu-shi, Gunma 376-8515, Japan;
Beilstein J Org Chem. 2014 Dec 16;10:2997-3006. doi: 10.3762/bjoc.10.318. eCollection 2014.
Poly(L-lactic acid) (PLLA) is a biodegradable plastic and one of the most famous plastics made from biobased materials. However, its physical strength is insufficient compared to general-purpose plastics. In this study, the effect of methylcyclodextrin (MeCD) addition on the structure and physical properties, especially the drawing behavior, of PLLA was investigated. Through thermal analysis, it was found that MeCD addition lowers the crystallinity and enhances the mobility of PLLA. The sample containing approximately 17% MeCD was drawn to more than 1000% at 60 °C, although PLLA fractured at a strain of less than 100%. Differential scanning calorimetry (DSC)-Raman in situ measurements also revealed decreases in the glass transition temperature (T g), cold crystallization temperature (T c), and melting point (T m), and improvement in structural distribution with temperature. DSC-Raman measurements simultaneously supplied information about crystallinity and thermal properties. Thus, it was concluded that MeCD had high affinity for PLLA, and the addition of MeCD increased the amorphous component of PLLA and enhanced the drawability.
聚（L-乳酸）（PLLA）是一种可生物降解的塑料，也是最著名的生物基材料制成的塑料之一。然而，与通用塑料相比，其物理强度不足。在这项研究中，研究了甲基环糊精（MeCD）添加对 PLLA 的结构和物理性能（尤其是拉伸行为）的影响。通过热分析发现，MeCD 的添加降低了 PLLA 的结晶度并提高了其分子的流动性。在 60°C 下，含有约 17%MeCD 的样品被拉伸至 1000%以上，尽管 PLLA 在应变小于 100%时就断裂了。差示扫描量热法（DSC）-拉曼原位测量还表明玻璃化转变温度（Tg）、冷结晶温度（Tc）和熔点（Tm）降低，并且结构随温度的分布得到改善。DSC-拉曼测量同时提供了结晶度和热性能的信息。因此，可以得出结论，MeCD 与 PLLA 具有高亲和力，添加 MeCD 增加了 PLLA 的无定形成分并提高了可拉伸性。
